When a user speaks in close proximity to a microphone, the user's voice acquires a more bass-heavy sound. This increase in low frequency response of the microphone may be referred to as proximity gain or the proximity effect. Because cardioid microphones are sensitive to proximity gain, such microphones may be equalized in a studio setting to avoid the effect for a user speaking a defined distance from the microphone.
When a microphone is used outdoors, wind may cause the microphone to pick up undesirable low-frequency noise. Equalizing down the low-frequency content from the microphone signal can reduce audible wind noise, but also reduces the useful response of the microphone when the wind is not present.